[pacman-dev] [PATCH] Introduce event types for start/end database list download

[Allan McRae]

On 6/5/20 11:28 am, Anatol Pomozov wrote:
>>> Multiplexed database/files downloads will use multiple progress bars.
>>> The UI logic is quite complicated and printing error messages while
>>> handling multiple progress bars is going to be challenging.
>>>
>>> Instead we are going to save all ALPM error messages to a list and flush
>>> it at the end of the download process. Use on_progress variable that
>>> blocks error messages printing.
>>>
>> This is going to be fun... If you have a 100 package update and your
>> first mirror is down, you will end up with 100 error messages at the
>> end.  e.g.
>>
>> $ sudo ./build/pacman -Sy
>> :: Synchronizing package databases...
>>  testing                45.4 KiB  24.5 KiB/s 00:02 [##############] 100%
>>  core                  134.6 KiB  61.8 KiB/s 00:02 [##############] 100%
>>  extra                1646.0 KiB   741 KiB/s 00:02 [##############] 100%
>>  community-testing     621.3 KiB   468 KiB/s 00:01 [##############] 100%
>>  community               4.9 MiB  2.12 MiB/s 00:02 [##############] 100%
>> error: failed retrieving file 'extra.db' from allanmcrae.com : The
>> requested URL returned error: 404
>> error: failed retrieving file 'testing.db' from allanmcrae.com : The
>> requested URL returned error: 404
>> error: failed retrieving file 'core.db' from allanmcrae.com : The
>> requested URL returned error: 404
>> error: failed retrieving file 'community-testing.db' from allanmcrae.com
>> : The requested URL returned error: 404
>> error: failed retrieving file 'community.db' from allanmcrae.com : The
>> requested URL returned error: 404
> I believe this is the same behavior as we currently have in the latest release.
> 

Yes - but the errors are spread through the output.  I was thinking of
an update of 100 packages, and suddenly this gets spewed out at the end.

>> This is patch is fine, but we should perhaps change the output to count
>> the failures from each server.
> Doing aggregation like this would be a bit tricky. The error message
> formatting happens at ALPM level when it calls _alpm_log() function.
> _alpm_log() calls handle->logcb() with a formatted string as an
> argument. So pacman has no reliable way to find out what was the error
> context. Pacman's responsibility at this point is just to collect the
> messages and print it without screwing up the UI.
> 
> Thus the error aggregation need to happen in dload.c and would require
> some refactoring.

Of course - I was not talking about it happening in this patch.  Just
flagging something of future polishing.

A